CONVECTION IN OBLATE SOLAR-TYPE STARS
CONVECTION IN OBLATE SOLAR-TYPE STARS
复制标题
扁太阳型恒星中的对流
DOI：
10.3847/0004-637x/830/1/45
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
C. Liang
中科院分区：
文献类型：
--
作者：
Junfeng Wang;M. Miesch;C. Liang
我们首次对快速旋转的太阳型恒星的扁圆包层中的热对流进行了全球 3D 模拟。这是通过利用新的可压缩高阶非结构化频谱差异 (CHORUS) 代码的功能来实现的。我们考虑自转速率高达临界（分裂）自转速率的 85%，这会产生比极地半径大 17% 的赤道半径。这种巨大的扁率增强了极地和赤道对流模式之间的差异。我们发现对流重新分配了从外表面发出的热通量，导致极地和赤道地区的热通量增强。这一发现意味着，具有对流包层的低质量恒星可能不会像经典重力变暗论证所预测的那样具有较暗的赤道。强烈的高纬度对流还在极地地区建立了细长的轴对称环流和纬向急流。尽管表面差动旋转的总振幅ΔΩ对扁率不敏感，但扁率确实将差动旋转中包含的分数动能限制在不超过61%。此外，我们认为这种水平的差异旋转不足以对恒星的扁率产生重大影响。
We present the first global 3D simulations of thermal convection in the oblate envelopes of rapidly rotating solar-type stars. This has been achieved by exploiting the capabilities of the new compressible high-order unstructured spectral difference (CHORUS) code. We consider rotation rates up to 85% of the critical (breakup) rotation rate, which yields an equatorial radius that is up to 17% larger than the polar radius. This substantial oblateness enhances the disparity between polar and equatorial modes of convection. We find that the convection redistributes the heat flux emitted from the outer surface, leading to an enhancement of the heat flux in the polar and equatorial regions. This finding implies that lower-mass stars with convective envelopes may not have darker equators as predicted by classical gravity darkening arguments. The vigorous high-latitude convection also establishes elongated axisymmetric circulation cells and zonal jets in the polar regions. Though the overall amplitude of the surface differential rotation, ΔΩ, is insensitive to the oblateness, the oblateness does limit the fractional kinetic energy contained in the differential rotation to no more than 61%. Furthermore, we argue that this level of differential rotation is not enough to have a significant impact on the oblateness of the star.
登录
查看更多内容
剪切和磁场对旋转球壳内对流换热效率的影响
影响因子：
2.8
作者：
Gastine;Christensen;Duarte;L. D. V;Reiners
通讯作者：
Reiners
影响因子：
4.8
作者：
Gastine, T.;Yadav, R. K.;Wicht, J.
通讯作者：
Wicht, J.
DOI：
10.1088/0004-637x/763/2/116
发表时间：
2013-01
期刊：
The Astrophysical Journal
影响因子：
--
作者：
D. Kong;Keke Zhang;G. Schubert;J. Anderson
通讯作者：
D. Kong;Keke Zhang;G. Schubert;J. Anderson
影响因子：
3.2
作者：
Jones, C. A.;Boronski, P.;Wicht, J.
通讯作者：
Wicht, J.